RCD tripping on lighting circuit

[The apprentice]

Hi there I have a problem with rcd tripping in a department store, I changed 2 old board which where re wire fuses to dual rcd boards which all the other circuits stand but 2 circuit breakers which one does a few track lights for display and the other does 2 led tornado fittings when I energies the tornado fittings it trips one side of the split rcd and when I energies the track lights it takes out two of the rcd at the same time, it’s a decent sized store and iam struggling to faukt find on it any help would be greatly appreciated

 

[SparkySy]

I take it you have checked for the usual suspects like insulation resistance & borrowed neutrals? If the RCDs are tripping! If it's mcbs how many fittings and what rating and type are the mcbs? Could be in-rush current if there are a lot of fittings!

 

[The apprentice]

I take it you have checked for the usual suspects like insulation resistance & borrowed neutrals?

I got to the job today because I was at another job one of the other guys got sent to my job to check it I’ve not met up with him yet but iam assuming he has done that and still not sorted

 

[littlespark]

Dual rcd boards could be affected by cumulative earth leakage across a number of circuits.

I would look for borrowed neutrals.... might be the case of doubling up a couple of circuits onto one.
Old stores would just have circuits added and modified as and when needed, quickly during closed, and no real design or testing done at the time.

 

[SparkySy]

I agree I've seen some right lash in jobs in the retail sector! Got to be done for opening up Monday morning no matter what!

 

[The apprentice]

Dual rcd boards could be affected by cumulative earth leakage across a number of circuits.

I would look for borrowed neutrals.... might be the case of doubling up a couple of circuits onto one.
Old stores would just have circuits added and modified as and when needed, quickly during closed, and no real design or testing done at the time.

Yeah my thought was maybe earth leakage but my mind was wondering to other things could it be possible to clamp the main earth in the board and see what iam getting down the earth or am I on the wrong path? Thanks a lot for the advice

 

[The apprentice]

I agree I've seen some right lash in jobs in the retail sector! Got to be done for opening up Monday morning no matter what!

Yeah this was a nightshift I was knackerd

 

[SparkySy]

I would say not as it may tell you some of the earth leakage but some will be lost to parallel paths. Usually you would clamp the live and neutral together for the circuit in question and look for the discrepancy. Tbh I have only used the conventional tried and tested methods for finding faults like this but they work without fail!

 

[The apprentice]

I take it you have checked for the usual suspects like insulation resistance & borrowed neutrals? If the RCDs are tripping! If it's mcbs how many fittings and what rating and type are the mcbs? Could be in-rush current if there are a lot of fittings!i

Dual rcd boards could be affected by cumulative earth leakage across a number of circuits.

I would look for borrowed neutrals.... might be the case of doubling up a couple of circuits onto one.
Old stores would just have circuits added and modified as and when needed, quickly during closed, and no real design or testing done

I would say not as it may tell you some of the earth leakage but some will be lost to parallel paths. Usually you would clamp the live and neutral together for the circuit in question and look for the discrepancy. Tbh I have only used the conventional tried and tested methods for finding faults like this but they work without fail!

Thanks a lot mate I have got alot to learn iam just trying to get there but by bit if I find will be sure to let you know

 

[SparkySy]

Never any harm in asking, life is one big learning curve, hell I'm still learning now and loving it!
Just take logical steps and you will sus it out, do let us know how you get on and what you find!
Best of luck?

 

[The apprentice]

Never any harm in asking, life is one big learning curve, hell I'm still learning now and loving it!
Just take logical steps and you will sus it out, do let us know how you get on and what you find!
Best of luck?

Will do buddy thank-you

 

[telectrix]

and don'tforget the schoolboy error of a N in the wrong bar.

 

[UNG]

Had something similar a while ago where we were putting in a couple of RCBO boards to replace the 3036 boards, it quickly became apparent the multi gang switches and neutrals were not properly paired up, the installation had a 6 gang and 13 gang switch (18 gang grid 13 used), the 6 gang had 2 banks of 3 switches on 2 lives and 2 neutrals this ended up as a bank of 2 and 4 to get the lives and neutrals paired, the 13 gang
had groups of 2, 3 or 4 switches on one live and 2 or 3 neutrals it took a little while to unravel and get the switches grouped across the 4 lives and 4 neutrals but got there in the end.
What was interesting was the 5 yearly EICR's for the last 20 years had not found it but that's another story